A precise and stable reference frequency is often desired, e.g., in a communication device required, by standard, regulation, or otherwise, to transmit at a specified frequency within a prescribed tolerance. For example, ETSI GSM Standard 05.10 specifies that the GSM air interface requires a frequency stability of ±0.1 ppm, and not meeting this specification at a base transceiver station (BTS) site can lead to dropped calls and other problems. A precise and stable reference frequency has been achieved through high-precision and high-stability reference oscillators, but these reference oscillators are exceedingly bulky, power inefficient, and/or expensive for many communication devices that require a precise and stable reference frequency. Global Positioning System (GPS) disciplined oscillators have also been used to provide reference frequencies, but GPS requires an unobstructed view of the sky, which may not be available to a communications or other equipment located in an interior office or apartment. Even if an unobstructed view of the sky is available, GPS is expensive and difficult to install. Therefore, there exists a need for an alternative way to provide a precise and stable reference frequency.